Impact of chronic kidney disease on recurrent ventricular tachyarrhythmias in ICD recipients

Mitochondrial DNA Polymorphisms of Peripheral Blood Mononuclear Cells Associated with Sustained Ventricular Tachycardia in Patients with Cardioverter-Defibrillator Implantation Indications

Background

Mitochondrial dysfunction in myocardium cells has been implicated in arrhythmogenesis, including ventricular tachycardia (VT). A carriage of point mitochondrial DNA (mtDNA) polymorphisms may contribute to the risk of certain arrhythmias. Therefore, it is hypothesized that mtDNA genotype could predict the risk of sustained VT (SVT). We aimed to explore whether specific mtDNA polymorphisms of peripheral blood mononuclear cells (PBMC) can serve as biomarkers for predicting the risk of SVT in patients with indications for an implantable cardioverter-defibrillator (ICD).

Methods

A total of 122 patients with ICD implantation indications who underwent transthoracic echocardiography (TTE) were enrolled in the study. Total DNA from PBMC was isolated using the phenol-chloroform extraction method. Genotyping of mtDNA polymorphisms A2706G, G3010A and G9055A was performed using restriction fragment length polymorphism analysis. Correlations between clinical parameters and mtDNA polymorphisms with SVT registered prior to ICD implantation were evaluated. Based on our data, we developed a risk model for SVT.

Results

Prior to ICD implantation, 70 (56.6%) patients had SVT (1st group) and 52 (43.4%) patients did not have SVT (2nd group). Patients with SVT were significantly older than patients without SVT (66.9 ± 9.9 year vs. 59.5 ± 10.6 year, p < 0.001), had a lower value estimated glomerular filtration rate (eGFR) (65.7 ± 19.7 mL/min/1.73 m2 vs. 77.9 ± 16.1 mL/min/1.73 m2, p < 0.001) and less frequently had A2706G mtDNA polymorphism (55.7% vs. 76.9%, p = 0.015). According to the multivariable logistic regression, age (odds ratio (OR) = 1.055, 95% confidence interval (CI) 1.009-1.103, p = 0.017), eGFR (OR = 0.974, 95% CI 0.949-0.999, p = 0.041) and absence of A2706G mtDNA polymorphism (OR = 0.335, 95% CI 0.141-0.797, p = 0.013) were independently associated with the SVT. We constructed a logistic equation with calculation of the cut-off value. The discriminative ability of the receiver operating characteristic curve (area under the curve) was 0.761 (95% confidence interval 0.675-0.833; sensitivity 65.71%; specificity 76.92%).

Conclusions

In patients with ICD implantation indications, a carriage of mtDNA polymorphism A2706G is associated with SVT. Our risk model including age, eGFR and absence of A2706G mtDNA substitution was able to distinguish patients with SVT. Further investigations of their predictive significance are warranted.

Clinical Trial Registration

NCT03667989 (https://clinicaltrials.gov/study/NCT03667989).

The Utility of Baseline Characteristics and [123I]MIBG Cardiac Adrenergic System Scintigraphy in Qualifying Patients with Post-Infarction Heart Failure for Implantable Cardioverter-Defibrillator (ICD) Placement

Background: Post-infarction heart failure with reduced ejection fraction (HFrEF) patients often face persistent risks of sudden cardiac arrest leading to sudden cardiac death. While implanting a cardioverter-defibrillator (ICD) can enhance prognosis, complications and costs limit its widespread use. Current patient qualification criteria, relying on imperfect parameters, require refinement. The impairment of the cardiac adrenergic system in heart failure is associated with ventricular arrhythmias. The goal of the study was to assess the utility of cardiac adrenergic system scintigraphy in qualifying patients for ICD placement. Methods: In this prospective study of 85 post-infarction HFrEF patients at a single center, clinical assessments, laboratory tests, echocardiography, [123I]MIBG scintigraphy, and ICD implantation were performed. Scintigraphy involved planar chest images and evaluating the heart-to-mediastinum ratio (H/M) and washout rate (WO). SPECT imaging assessed [123I]MIBG uptake in 17 left ventricular segments to calculate the summed difference score (SDS). Results: During a median of 4-year follow-up, 22% of patients experienced appropriate ICD interventions, and 25% of patients died or underwent heart transplantation. The mean values of analyzed parameters did not significantly differ between groups. In the univariate analysis, younger age and moderately impaired left ventricular ejection fraction (LVEF) were correlated with more frequent ICD interventions. In comparison, older age and elevated NT-proBNP levels were associated with death or heart transplantation. Additionally, the univariate analysis identified SDS-15' as a prognostic factor for death/heart transplant. The multivariate analysis identified predictors for ICD interventions, including younger age, an EF of 30% or greater, and a larger left ventricular end-diastolic diameter. In contrast, older age and an LVEF of less than 25% were significant predictors of death or heart transplantation. Conclusions: Scintigraphic parameters did not effectively predict ICD interventions or death/heart transplantation, though the summed difference score demonstrated potential as a prognostic factor. Younger age with moderately impaired EF correlated with frequent ICD interventions, while in older age, EF < 25% predicted death or transplantation. Further investigation is needed for patients with borderline EF values.

Contemporary Management and Prognostic Factors of Arrhythmia Recurrence in Patients with High-Energy Discharge of Cardiac Implantable Electronic Devices

Background and Objectives: Understanding the underlying causes of implantable cardioverter-defibrillator (ICD) discharges is vital for effective management. This study aimed to evaluate the characteristics of patients admitted following ICD discharge, focusing on myocardial ischemia as a potential exacerbating factor and potential risk factors for VT recurrence. Materials and Methods: This retrospective, single-center study included 81 patients with high energy discharge from cardiac implantable electronic device admitted urgently to the cardiology department from 2015 to 2022. The exclusion criterion was ST-segment elevation acute coronary syndrome. Data were collected anonymously from electronic medical records. Patients were categorized based on coronary angiography, percutaneous angioplasty, presence of significant stenosis, recurrent ventricular tachycardia (VT), and catheter ablation. Clinical variables, including demographic data, echocardiographic parameters, and pharmacotherapy, were analyzed. The primary endpoint was the recurrence of VT during in-hospital stay. Results: Among 81 patients, predominantly male (86.4%), with a mean age of 63.6 years, 55 (67.9%) had coronary artery disease (CAD) as the primary etiology for ICD implantation. Coronary angiography was performed in 34 patients (42.0%) and showed significant stenosis (>50%) in 18 (41.8%) patients, while 8 (26.0%) individuals underwent percutaneous coronary intervention (PCI). Recurrent VT occurred in 21 subjects (26.3%), while ventricular catheter ablation was performed in 36 patients (44.0%). Referral for urgent coronary angiography was associated with presence of diabetes (p = 0.028) and hyperlipidemia (p = 0.022). Logistic regression analysis confirmed NYHA symptomatic class (OR 4.63, p = 0.04) and LVH (OR 10.59, p = 0.049) were independently associated with relapse of VT. CAD patients underwent catheter ablation more frequently (p = 0.001) than those with dilated cardiomyopathy. Conclusions: The study showed a low referral rate for coronary angiography among patients with ICD discharge. Presence of LVH and preexisting symptomatic class influence arrhythmia recurrence. Understanding these associations can guide personalized management strategies for ICD recipients.

Anti-tachycardia pacing for non-fast and fast ventricular tachycardias in individual Japanese patients: From Nippon-storm study

BACKGROUND

Anti-tachycardia pacing (ATP) delivered from an implantable device is a useful tool to terminate ventricular tachycardia (VT). But its real-world efficacy for those patients having multiple VTs with varying VT rates has not been fully studied.

METHODS

Using the Nippon-storm study database, efficacy of patient-by-patient basis ATP programing for Japanese patients having both non-fast (120-187 bpm) and fast VT (≥188 bpm) was assessed. According to the useful criteria of ≥50% success termination by ATP, patients were divided into three subgroups; success ≥50% for both non-fast and fast VT (both useful), ≥50% only for non-fast VT (non-fast VT useful), or ≥50% for neither non-fast nor fast VT (neither useful).

RESULTS

During a median follow-up of 28 months, ATP terminated 184 of the 203 non-fast VT episodes (91%) and 86 of the 113 fast VT episodes (76%) in all 41 patients. In the patient-by-patient analysis, efficacy of ATP was not different between non-fast and fast VT in most of the patients (36/41 = 88%); 32 patients were in the both useful and four other patients in the neither useful. Neither ischemic nor non-ischemic structural heart disease was associated with the ATP efficacy, whereas LVEF more than 37.0% and non-prescribed amiodarone were characteristics of the patients classified into the both useful.

CONCLUSIONS

ATP well terminated both non-fast and fast VT occurring in individual Japanese patients with various structural heart diseases in the real-world device treatment and this finding further supports ATP programing for all device tachycardia detection zones in most patients with multiple VTs.

Implantable Cardioverter Defibrillators and Chronic Kidney Disease

Use of implantable cardioverter defibrillators (ICDs) is the treatment of choice for heart failure patients with ejection fraction <35% to prevent sudden cardiac death. Whether this benefit remains among patients with chronic kidney disease (CKD) or end stage renal disease (ESRD) is yet to be elucidated. We conducted a systematic review of studies in PubMed that have investigated the use of ICDs among patients with CKD or ESRD. From the 470 studies identified, we selected 42 for the current review. Patients with CKD/ESRD were more likely to get antitachycardia pacing or shocks and had higher cardiac and/or all-cause mortality compared to patients without CKD/ESRD. These associations had an inverse dose-response effect with worse outcomes with decreasing kidney function. In conclusion, use of ICDs in CKD/ESRD is associated with increased antitachycardia pacing/shocks and mortality suggesting that their routine use in this patient population may be associated with more adverse outcomes than benefits.

Chronic kidney disease impairs prognosis in electrical storm

Background

The study sought to assess the prognostic impact of chronic kidney disease (CKD) in patients with electrical storm (ES). ES represents a life-threatening heart rhythm disorder. In particular, CKD patients are at risk of suffering from ES. However, data regarding the prognostic impact of CKD on long-term mortality in ES patients is limited.

Methods

All consecutive ES patients with an implantable cardioverter–defibrillator (ICD) were included retrospectively from 2002 to 2016. Patients with CKD (MDRD-GFR < 60 ml/min/1.73 m²) were compared to patients without CKD. The primary endpoint was all-cause mortality at 3 years. Secondary endpoints were in-hospital mortality, cardiac rehospitalization, recurrences of electrical storm (ES-R), and major adverse cardiac events (MACE) at 3 years.

Results

A total of 70 consecutive ES patients were included. CKD was present in 43% of ES patients with a median glomerular filtration rate (GFR) of 43.3 ml/min/1.73 m². CKD was associated with increased all-cause mortality at 3 years (63% vs. 20%; p = 0.001; HR = 4.293; 95% CI 1.874–9.836; p = 0.001) and MACE (57% vs. 30%; p = 0.025; HR = 3.597; 95% CI 1.679–7.708; p = 0.001). In contrast, first cardiac rehospitalization (43% vs. 45%; log-rank p = 0.889) and ES-R (30% vs. 20%; log-rank p = 0.334) were not affected by CKD. Even after multivariable adjustment, CKD was still associated with increased long-term mortality (HR = 2.397; 95% CI 1.012–5.697; p = 0.047), as well as with the secondary endpoint MACE (HR = 2.520; 95% CI 1.109–5.727; p = 0.027).

Conclusions

In patients with ES, the presence of CKD was associated with increased long-term mortality and MACE.

Association between CRT(D)/ICD and renal insufficiency: A systematic review and meta-analysis

Cardiac resynchronization therapy with or without a defibrillator (CRT(D)) and implantable cardioverter defibrillator (ICD) may reduce the risk of arrhythmia or heart failure-specific mortality and improves the prognosis of patients with chronic kidney disease (CKD) or dialysis. The aim of this study was to perform a meta-analysis investigating the relationship between CRT(D)/ICD and renal insufficiency. Cochrane Library, Web of Science, Embase, and Pubmed were systematically searched from inception to 29 October 2019. We included studies that report all-cause mortality of patients with renal insufficiency who received CRT(D)/ICD therapy. Twenty-six studies (n = 119,263) were included, exploring the relationship between CRT(D)/ICD and renal insufficiency from two aspects: (1) Compared with ICD-only, CRT(D) was associated with lower risk of all-cause mortality in CKD patients (odds ratios (OR) = 0.67; 95% confidence interval (CI), 0.60 to 0.75). For non-primary prevention (secondary prevention or both), the analysis revealed a lower risk of all-cause mortality in the ICD group than in the no-ICD group (OR = 0.47; 95% CI, 0.40 to 0.55). (2) CKD increased all-cause mortality in comparison with control group (OR = 2.12; 95% CI, 1.85 to 2.44), and so did dialysis (OR = 2.53; 95% CI, 2.34 to 2.73). Furthermore, compared with CKD3 (eGFR: 30-59 ml/min/1.73 m² ), CKD4/5 (eGFR <30 ml/min/1.73 m² ) was observed to have a significantly higher risk of all-cause mortality (OR = 2.70; 95% CI, 1.93 to 3.80). This review shows a clear association between CRT(D)/ICD and renal insufficiency in the aspect of all-cause mortality, and may provide a reference for the clinical application of CRT(D)/ICD.

Aortic Stiffness and Heart Failure in Chronic Kidney Disease

Purpose of Review

To provide an update on the recent findings in the field of aortic stiffness and heart failure in patients with chronic kidney disease (CKD).

Recent Findings

Stratification of cardiovascular risk in CKD remains an open question. Recent reports suggest that aortic stiffness, an independent predictor of cardiovascular events in many patient populations, is also an important prognostic factor in CKD. Also, novel measures of myocardial tissue characterization, native T1 and T2 mapping techniques, have potential as diagnostic and prognostic factors in CKD.

Summary

Cardiovascular magnetic resonance has the ability to thoroughly evaluate novel imaging markers: aortic stiffness, native T1, and native T2. Novel imaging markers can be used for diagnostic and prognostic purposes as well as potential therapeutic targets in CKD population.